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摘要
In permafrost regions, embankment stability has been destroyed with longitudinal cracks primarily caused by transverse asymmetric settlement. And shady-sunny slope effect is a principal factor which might result in embankment asymmetric settlement. Based on field data of some typical sections along the Chai-Mu Railway (simply called CMR) with obvious shady-sunny slopes, which is located on the Qinghai-Tibet Plateau, the ground temperature characteristics and settlement deformation properties of the embankment have been analyzed. This paper has studied how the different engineering measures, including rubble ventilation embankment, thermal pipe revetment embankment, rubble and thermal pipe revetment joint embankment, did influence the shady-sunny slope effect The results show that: (1) Both thermal pipe revetment embankment and rubble ventilation embankment have perfect effect on cooling the roadbed in permafrost regions. However, for thermal pipe revetment embankment, the sunny-shady phenomenon and asymmetric settlement of embankment have been avoided if thermal pipe has been strengthened in sunny side. For rubble ventilation embankment, the sunny-shady effect has been hardly eliminated even though the rubble has been strengthened in sunny side. Although some composite embankments, such as the rubble and thermal pipe revetment joint embankment, have been successfully applied in the Qinghai-Tibet Railway, it is difficult to completely eliminate the sunny-shady slope problem along the CMR because of the complicated engineering geological conditions and the bad permafrost environments. (2) Along the CMR, in all common embankments the observed results show that the settlement deformation is within 30 cm that is within the settlement standards of the National II Class Railway. Even the settlement deformation of thermal pipe subgrade and rubble ventilation embankment was able to meet the National I Class Railway standards 20 cm. (3) On the basis of the above, some corresponding countermeasures and advice are proposed. First, rational use of the synthetic application of engineering measures must be taken. For example, let the structural mechanics measures and temperature controlled measures unify altogether to prevent longitudinal cracks. Second, the specific work conditions and details such as engineering geological condition, permafrost environments as well as other local factors including the slope orientation have to be taken into account in order to put forward rational engineering measures and accurate design parameters. Finally, it is essential to protect and to comprehensively evaluate the permafrost environment, which is the ultimate basis of permafrost engineering.
- 出版日期2015-2
- 单位兰州理工大学; 中国科学院地质与地球物理研究所兰州油气资源研究中心
